<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    var date1 = new Date('1970-1-1');//UTC+8
    var t1 = date1.getTime();
    var fc = date1.getTimezoneOffset();
    console.log(fc/60);

    var t2 = Date.UTC(1970,0,1);

    console.log(t1);
    console.log(t2);
</script>
</body>
</html>